The invention concerns a cup-shaped valve tappet for activation of a gas exchange valve of an internal combustion engine. The valve tappet includes a hollow cylinder closed on one end by a base with a device for automatic hydraulic valve play compensation which occurs in relation to a cam of a camshaft being arranged in the interior, which basically includes:
a thin-walled funnel which extends from an internal casing jacket surface of the hollow cylinder toward the base, and ends as a guide casing which is concentric to the hollow cylinder, PA1 play compensation element arranged in the guide casing, PA1 a diverting element which lies on an interior side of the base by means of a disk-like section, whereby an inner shell extends from the disk-like section which overlaps with the guide casing while forming an axial channel outside, and whereby the inner casing is surrounded by a ring-shaped oil storage space which can be fed a hydraulic medium through a bore hole provided in the hollow cylinder.
A valve tappet of this type is known from DE 38 10 436. By means of the inner casing which extends from the walls of the funnel bounding the annular oil storage space from below, air reaching into a central oil storage space of the valve play compensation element is supposed to be prevented. This air can be present in the annular oil storage space following a stoppage of the internal combustion engine. Since only the oil from the base area of the funnel reaches into the central oil storage space through the axial channel formed between the inner shell and the guide casing, an in-flow of air can be effectively avoided. In addition, this publication discloses a disk-like element associated with the inner shell which lies on the base of the valve tappet and in this way serves to guide and fix the inner shell. It has been shown that under certain installation conditions of the internal combustion engine, as for example, in relation to vertically tipped cylinder units and extremely obliquely positioned gas exchange valves, the problem that the annular oil storage space can empty during a stoppage of the internal combustion machine can still occur. Following a subsequent starting of the engine, an increased valve play then occurs which is associated with valve operation tapping noises.
Furthermore, providing cup-shaped valve tappets with a diverter in the area of the bore hole which should prevent the annular oil storage space from becoming empty is known. This diverter is constructed together with the funnel and causes an increase in the weight of the cup-shaped valve tappet. Since the funnel must specifically possess a sufficient rigidity for guidance of the valve play compensation element, it is constructed with thicker walls than the diverting element, which serves exclusively for directing the hydraulic fluid or medium. Furthermore, such a one piece construction of the funnel with the outer diverting element is associated with a complicated construction of the funnel and causes a difficult assembly in the cup tappet.